Vacuum powered lifting and transport systems are known in the prior art. One example is shown in U.S. Pat. No. 4,413,853, S. Andersson, Nov. 8, 1983, wherein a tubing that changes length with internal air pressure is shortened by means of a vacuum source to lift a work object by vacuum suction and transport it to another location.
While these vacuum powered type of lifting and transport systems have advantages in engaging, lifting and transporting work load objects weighing 200 pounds or more along assembly lines in a factory, for example, several problems and deficiencies are present in such prior art systems that have limited their usefulness. Some limitations have made such systems potentially dangerous, in that heavy work load objects are critical to control and may be inadvertently dropped from the lifting mechanism or inaccurately positioned with uncontrollable speed.
It has been found in accordance with this invention for example that air pressure control systems employed in vacuum powered lifts to engage, lift, transport and release heavy work load objects have critical ranges of load positioning and work object grasping and releasing procedures requiring significant concentration and skill by an operator. In particular, operators must become very skilled in controlling air pressure changes particularly when lowering heavy work load objects to a terminal location under transition conditions from near atmospheric pressure to minimum pressures supplied by a vacuum source, to prevent premature release or mispositioning of the work object, which can impact with accompanying danger of damage to equipment or operator.
Criticality in atmospheric controls in such systems also are encountered as well as other deficiencies, such as (1) variations in performance and positioning of the lifting mechanism when loaded and unloaded; (2) the possibility of work object grasping failures; and (3) malfunctioning or mispositioning due to critical manual operational conditions in pressure control mechanisms.
It is therefore an object of the invention to provide improved vacuum powered lift and transport systems and controls overcoming the foregoing problems encountered in the prior art.
Other objects, features and advantages of the invention will be found throughout the following description, drawings and claims.